This research explores the feasibility of using a novel electrochemical sensor for monitoring the alcohol content in breath. Successful demonstration during the Phase I program of the proposed sensor's response, precision, accuracy, detectivity, life and tolerance to interferences would lead to a Phase II program to develop a computerized instrument for the measurement of alcohol treatment compliance. The proposed Phase II instrument would utilize the sensor developed in Phase I and would be capable of three functions. The patient would communicate with the microprocesser via a microphone and a liquid crystal display. The microphone would also contain the alcohol sensor so that the identity of the user as well as his breath alcohol level could be simultaneously measured. The patient would be asked to play games and his speed and accuracy monitored. These data along with the time and day would be stored on tape for later computer analyses by the physician's computer. The importance of the proposed research lies in the fact that only the lack of a portable, sensitive, rapidly responding and inexpensive alcohol sensor prevents the development of a wide range of commercial products including a hand held ethanol for police inspections, a video game to check impairment as well as breath alcohol level, systems for preventing the operation of motor vehicles while under the influence, as well as instruments for public health research into alcohol abuse and treatment.